PURPOSE: In the U.S. and globally, adults independently seek out online advice to support their personal health and fitness goals. In this study, we examined web articles specific to physical activity promotion. Our objectives were to determine the rate that web articles at least once provided advice consistent with national physical activity guidelines (PAGs) and determine if consistency with PAGs varied on the basis of production source (i.e., commercial, governmental, professional association, or voluntary health agency). METHODS: The Google search engine was used to locate free-to-access web articles focused on physical activity promotion, written in English, and used text as the main communication medium. Valid lay search strategies independently reviewed by three experts were used. The 2008 Physical Activity Guidelines for Americans 18 to 64 years of age were used to appraise the credibility of messages. Seventeen potential PAGs were referenced. RESULTS: A sample of 72 web articles published or updated between 2008 and 2018 was obtained (M = 2016.34, SD = 2.02). All web articles that comprised the sample presented PAG-related messages. The percent of the sample that lacked at least one consistent message ranged from 61.1% to 100% across the 17 PAGs. The level of inconsistency was significant for 15 PAGs, all p < .05. Production source was associated with consistency for five PAGs, all related to aerobic (endurance) physical activity, p ≤ .05, Cramer’s V ≥ .30. For the remaining 12 PAGs, the rate of consistency was equivalent across the production source groups, p > .05, Cramer’s V = .11-.26. Message consistency was lowest with guidelines for adults who have sedentary or modestly active lifestyles, M ≈ 3% of the study sample. CONCLUSION: Knowledge translation of physical activity guidelines is low in free online resources that lay adults may independently locate. This observation was irrespective of production source. The implications of this study’s results will be discussed, including ways that they pertain to ACSM’s National Roadmap to Improve Equity in Physical Activity Participation. In consideration of this study’s findings, as well as broader knowledge translation issues that have been raised by others, including in other countries (e.g., Canada), recommendations for future research will be provided.